AuthenticationProtocol

Protocol for pluggable authentication strategies.

Strategies are responsible for:
1. Detecting if they can handle a request (via supports())
2. Extracting user identity from the request (via authenticate())

The framework uses multiple strategies in a chain. The first strategy
that supports the request and successfully authenticates wins.

Methods:
    supports: Check if this strategy can handle the request
    authenticate: Extract user identity from request

Example implementation:
    class BearerTokenAuth:
        def supports(self, headers: Mapping[str, str]) -> bool:
            auth_header = headers.get("authorization", "")
            return auth_header.startswith("Bearer ")

        async def authenticate(
            self, headers: Mapping[str, str]
        ) -> UserContext | None:
            token = headers.get("authorization", "")[7:]
            # Validate token and return user...

Source: authentication.py

Methods

supports

def supports(self, headers: Mapping[str, str]) -> bool

Check if this strategy can handle the request.

    Called before authenticate() to determine if this strategy
    should be used. Should be a fast, synchronous check.

    Args:
        headers: Request headers (lowercase keys)

    Returns:
        True if this strategy can handle the request

authenticate

async def authenticate(self, headers: Mapping[str, str]) -> UserContext | None

Authenticate the request and extract user identity.

    Called only if supports() returned True.

    Args:
        headers: Request headers (lowercase keys)

    Returns:
        UserContext if authentication successful, None otherwise